1. Field of the Invention
The invention relates to an apparatus for measuring gases dissolved in water using a gas exchanger to which the water to be tested can be supplied via a water line and a carrier gas can be supplied via a gas line, and in which leading away from the gas exchanger, besides a drainage line for degassed water, is a drainage line for washed-out gas, which communicates via a gas dryer with analysis and measuring instruments.
2. Description of the Prior Art
German patent disclosure document DE-OS No. 33 36 423 discloses an apparatus of this kind. Here argon is delivered as the carrier gas to the gas exchanger, called a contact cell; the argon then entrains the gases present in the water sample. This gas mixture is dried and then chromatically separated in a separation column. The washed-out gases are detected quantitatively by means of thermal conductivity detectors.
The known contact cell comprises a cylindrical portion in which spirally wound tubes extend. The two tubes, one of which carries the water to be tested and the other carries argon, have openings distributed uniformly over their circumference. As a result, water and argon come into contact, and the gases dissolved in the water are washed out by the argon. A gas removal line communicates with a flange on the housing, and the washed-out gas can be delivered through this gas removal line to a gas chromatograph, for example.
In a contact cell of this kind, the gas exchange is effected only up to an initially unknown equilibrium. The location of this equilibrium and hence the efficiency of the apparatus must be ascertained by calibration.
Since an apparatus for collecting the waste water and the waste gas is lacking, the known apparatus is unsuitable for monitoring contaminated water. For example, various kinds of gases are dissolved in the primary coolant of light or heavy water reactors, and for such gases it is desirable to monitor their concentration. Hydrogen and oxygen can be produced by radiolysis of water. In pressurized water reactors, the radiolysis of the primary coolant is limited. Nevertheless, the limit values of the hydrogen and oxygen concentration must be monitored. In particular, the concentration of oxygen, which is responsible for corrosion, must be monitored. The proportion of nitrogen in the primary coolant must also be monitored. Nitrogen is partly responsible for fuel element corrosion. If there is damage to the fuel elements, the noble gases krypton and xenon enter the primary coolant. An indication of the status of the fuel elements can be gained by ascertaining the concentrations of krypton and xenon.